Hesperaletes (Mammalia: Perissodactyla), a new tapiroid from the middle Eocene of southern California

Two new species of tapiroid perissodactyls referred to Hesperaletes gen. nov. are described from the Uintan of southern California. Hesperaletes has a deeply retracted narial incision, which is an indicator of prehensile proboscis development. This feature also characterizes early Oligocene Protapirus from North America and has been used to diagnose Tapiridae. All late Uintan samples from San Diego County, California, are referred to H. borineyi sp. nov., but anomalous patterns of variability and morphological variation prohibit referral of much smaller early Uintan samples to a single species. Most of the early Uintan samples are referred to H. walshi sp. nov. with the exception of one sample, which is referred to cf. Hesperaletes. North American Protapirus and Hesperaletes show many cranial similarities, and phylogenetic analysis resolves them as members of an unnamed clade, implying that Hesperaletes is a tapirid.